/*
 * Copyright (C) 2016 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.graph;

import java.util.Set;
import javax.annotation.CheckForNull;

/**
 * A class to allow {@link ValueGraph} implementations to be backed by a provided delegate. This is
 * not currently planned to be released as a general-purpose forwarding class.
 *
 * @author James Sexton
 * @author Joshua O'Madadhain
 */
@ElementTypesAreNonnullByDefault
abstract class ForwardingValueGraph<N, V> extends AbstractValueGraph<N, V>
{

    abstract ValueGraph<N, V> delegate();

    @Override
    public Set<N> nodes()
    {
        return delegate().nodes();
    }

    /**
     * Defer to {@link AbstractValueGraph#edges()} (based on {@link #successors(Object)}) for full
     * edges() implementation.
     */
    @Override
    protected long edgeCount()
    {
        return delegate().edges().size();
    }

    @Override
    public boolean isDirected()
    {
        return delegate().isDirected();
    }

    @Override
    public boolean allowsSelfLoops()
    {
        return delegate().allowsSelfLoops();
    }

    @Override
    public ElementOrder<N> nodeOrder()
    {
        return delegate().nodeOrder();
    }

    @Override
    public ElementOrder<N> incidentEdgeOrder()
    {
        return delegate().incidentEdgeOrder();
    }

    @Override
    public Set<N> adjacentNodes(N node)
    {
        return delegate().adjacentNodes(node);
    }

    @Override
    public Set<N> predecessors(N node)
    {
        return delegate().predecessors(node);
    }

    @Override
    public Set<N> successors(N node)
    {
        return delegate().successors(node);
    }

    @Override
    public int degree(N node)
    {
        return delegate().degree(node);
    }

    @Override
    public int inDegree(N node)
    {
        return delegate().inDegree(node);
    }

    @Override
    public int outDegree(N node)
    {
        return delegate().outDegree(node);
    }

    @Override
    public boolean hasEdgeConnecting(N nodeU, N nodeV)
    {
        return delegate().hasEdgeConnecting(nodeU, nodeV);
    }

    @Override
    public boolean hasEdgeConnecting(EndpointPair<N> endpoints)
    {
        return delegate().hasEdgeConnecting(endpoints);
    }

    @Override
    @CheckForNull
    public V edgeValueOrDefault(N nodeU, N nodeV, @CheckForNull V defaultValue)
    {
        return delegate().edgeValueOrDefault(nodeU, nodeV, defaultValue);
    }

    @Override
    @CheckForNull
    public V edgeValueOrDefault(EndpointPair<N> endpoints, @CheckForNull V defaultValue)
    {
        return delegate().edgeValueOrDefault(endpoints, defaultValue);
    }
}
